#include <cctype>
#include <cstdio>
using namespace std;


int main(){

}

int readint(){
    int x=0,w=1;
    char ch=0;
    while(!isdigit(ch)){
        if(ch=='-')w=-1;
        ch=getchar();
    }
    while(isdigit(ch)){
        x=x*10+(ch-'0');
        ch=getchar();
    }
    return x*w;
}